Within living memory policing in Northern Ireland looked like a war zone with armed soldiers, checkpoints, and armoured landrovers driving snatch squads around to support regular foot patrols. And this was when times were good.
At other times it was violent, and sometimes deadly, and although by 1998 it had long been clear no military solution was possible to both the IRA and loyalist paramilitaries, the three-decades long conflict seemed intractable.
This is why the Good Friday agreement, which ended it all after years in the making, is so important, and why its 20th anniversary is worth honouring.
Some of the people, sworn enemies until brought to the negotiating table by Tony Blair and former US Senator George Mitchell, are no longer alive, but they might quaver at the risks the agreement faces.
Peace holds, even if the cultural change is slow in coming, and the deal has been held up since its forging as an international template for conflict resolution, setting an effective example that can and has been used in conflict resolution elsewhere.
But Brexit puts all that in doubt because of the border issue, and because some in Britain seem willing to play party politics with what should be a bipartisan question; keeping the peace.